In endoscopic surgical procedures, a trocar is inserted into the body, such as through the abdominal wall, in order to perform minimally invasive surgery or diagnostic procedures. As a preliminary step, pneumoperitoneum is often created by inserting a needle, such as a Verres needle, and introducing a gas to the peritoneal cavity to cause the abdominal wall to separate from the internal organs. The trocar generally consists of a guide tube housing having a central aperture aligned with a distally extending guide tube, and a sealing member associated with the central aperture. The trocar also includes an obturator housing having a distally extending obturator. The obturator has a sharp tip and is configured and dimensioned to be received through the guide tube housing aperture and the guide tube. In the assembled position ready for use, the sharp tip protrudes from the distal end of the guide tube. The trocar is inserted into the body by pressing the trocar against the patient's skin, causing the protruding obturator to make an incision in the skin so that the guide tube can penetrate the body. After penetration, the obturator assembly is removed from the guide tube housing, leaving the guide tube housing with the guide tube extending into the peritoneal cavity. Trocars of this type are generally shown and described in U.S. Pat. Nos. 4,601,710 and 4,654,030. The sealing member maintains a seal around the obturator during insertion into the abdomen, and is configured to maintain the seal after the obturator is removed. Surgical instruments designed to be inserted through the guide tube are used to perform endoscopic surgical or diagnostic procedures through the guide tube. Although trocars are discussed herein primarily with reference to abdominal surgery, it will be understood that the present invention will find application to any use of a trocar, regardless of the surgical procedure or anatomical location.
As stated, during endoscopic procedures the peritoneal cavity is normally inflated. Consequently, it is essential to maintain a tight seal of the cavity at all times, i.e., during insertion of the trocar, after insertion of the trocar with the obturator removed from the guide tube, and during surgical procedures performed with instruments inserted through the guide tube. In order to ensure a proper seal between the guide tube and surgical instruments inserted therein, the guide tube, guide tube housing, obturator, sealing member and surgical instruments are all designed and manufactured to close tolerances. By way of example, a variety of different diameter guide tube/obturator assemblies are supplied in order to accommodate myriad size instruments while maintaining pneumoperitoneum. The inner diameter of the guide tubes increase in very fine increments, such as one or two millimeters.
In order to maintain pneumoperitoneum, it is essential that surgical instruments are used only with the proper corresponding guide tube. In the case of the trocar including a guide tube housing and obturator assembly, use of the proper obturator with the appropriate corresponding guide tube housing generally is assured by making trocars available in pre-packaged ready-to-use units.
Unfortunately, however, a manufacturer cannot be confident that a surgical instrument to be inserted through a guide tube will be used in conjunction with the appropriate size guide tube. While it is true that surgical instruments to be inserted through a guide tube are manufactured to close tolerances set in conjunction with the corresponding guide tube, the manufacturer cannot be certain that the instrument will not be inserted into a guide tube of oversize diameter or used with a guide tube assembly from another manufacturer having different or less precise guide tube diameters and/or sealing member specifications. As will be readily appreciated, it is possible to insert an instrument into an oversized guide tube with possible loss of pneumoperitoneum. In case of insertion of an instrument into a trocar guide tube from an unknown source, the surgical instrument manufacturer has no control over the specifications and tolerances of the trocar guide tube or sealing member, which means a trocar ostensibly having the proper diameter guide tube for the instrument may in fact be too large or may have inadequate sealing characteristics. In either case, there is a hazard that a mis-match may be made of the outer diameter of the surgical instrument on the one hand and the guide tube and sealing member on the other. Such a mis-match may give rise to an improper or inadequate seal. Unfortunately, any significant loss of pressure at the sealing member can lead to desufflation of the peritoneal cavity, which will interfere with the surgeon's ability to operate, prolong the surgical procedure, and prolong the patient's exposure to anesthesia. In addition, undeserved damage may accrue to the good name of the surgical instrument manufacturer due to use of the instrument with a trocar of improper size or an inferior or inappropriate trocar.
Therefore, there presently exists a need to ensure that surgical instruments are used only in conjunction with the proper size guide tube having adequate sealing characteristics.
Accordingly, it is an object of the invention to provide an apparatus to ensure that endoscopic surgical instruments are used only with the corresponding guide tube of proper size and sealing characteristics.
Another object of the invention is to provide a surgical instrument/trocar guide tube matching device which does not interfere or inconvenience the user.
These and other objects of the invention are accomplished in a device which is relatively inexpensive to make and convenient to use without special training, but which alerts the user to a situation where a surgical instrument has been or is about to be inserted into an inappropriate trocar guide tube. Thus, the invention prevents inadvertent and undesirable insertion of a surgical instrument into an inappropriate guide tube and any resulting compromise of the seal between the instrument and trocar guide tube.
Objects and advantages of the invention are set forth in part herein and in part will be obvious herefrom, or may be learned by practice with the invention.